Do we have any electrical/electronics gurus out there? I have run into an issue and could use some knowledgeable help.
Here's what I've got going, a linear actuator for flaps tied to a gauge to read flap position off the actuator:
-12v linear actuator with 5v in position feedback (potentiometer) with 4" travel, . It's supposed to be a 0-10k ohm but it's a shorter travel version. I'm seeing:
-9400 ohm retracted, 7800 ohm extended between the 5v in and wiper/reference
-500 ohm retracted, 2100 ohm extended between "ground' and wiper/reference
-UMA flap position gauge, supposed to be 0-5k ohm, has a 5v out to the pot, marked 0-60 degrees travel
When I hook up the gauge to the actuator as designed, the voltage from gauge drops to 3.8v at input to pot.
-Gauge reads 10 degrees with actuator retracted and 50 degrees with actuator fully extended
-voltage in to reference (wiper) line on gauge from pot goes from .2 V retracted to .82 V extended
Separately I determined with my power supply that the gauge needs .1 V for 0 degrees flaps and 1.03 V for 60 degrees flaps in to the reference/wiper wire. I don't know if the gauge reads voltage or resistance but I can control it with voltage in from my DC power supply.
The problem: The way the flap linkage works, full 60 degrees of flaps occurs at the full retracted actuator position (so I need reverse polarity) and I need the full gauge reading 0-60 degrees in only 2" of travel rather than the 4" it has available.
When I reverse polarity to the pot on the actuator, the voltage still drops to 3.8 V in, but the voltage to the reference input of the gauge is now 3.75 v retracted and 3.55 V at full 4" extension. The gauge is pegged out the entire time.
My attempt: many things, but I found that adding a 1k ohm resistor in parallel brought the voltage do the gauge in to working range (.1-1.03V) but the only .2 V difference between retracted and extended actuator means the gauge barely moves.
Additional info: I connected the gauge to a 1k ohm rotary potentiometer, the 5V from the gauge dropped to about 1.4 V approx at the input to the pot and I was able to control the gauge/reference voltage through it's entire range easily.
Can anyone help with what I should do here? Sorry for the long post but this is a technical problem (for me).
Thank you,
Justin
Here's what I've got going, a linear actuator for flaps tied to a gauge to read flap position off the actuator:
-12v linear actuator with 5v in position feedback (potentiometer) with 4" travel, . It's supposed to be a 0-10k ohm but it's a shorter travel version. I'm seeing:
-9400 ohm retracted, 7800 ohm extended between the 5v in and wiper/reference
-500 ohm retracted, 2100 ohm extended between "ground' and wiper/reference
-UMA flap position gauge, supposed to be 0-5k ohm, has a 5v out to the pot, marked 0-60 degrees travel
When I hook up the gauge to the actuator as designed, the voltage from gauge drops to 3.8v at input to pot.
-Gauge reads 10 degrees with actuator retracted and 50 degrees with actuator fully extended
-voltage in to reference (wiper) line on gauge from pot goes from .2 V retracted to .82 V extended
Separately I determined with my power supply that the gauge needs .1 V for 0 degrees flaps and 1.03 V for 60 degrees flaps in to the reference/wiper wire. I don't know if the gauge reads voltage or resistance but I can control it with voltage in from my DC power supply.
The problem: The way the flap linkage works, full 60 degrees of flaps occurs at the full retracted actuator position (so I need reverse polarity) and I need the full gauge reading 0-60 degrees in only 2" of travel rather than the 4" it has available.
When I reverse polarity to the pot on the actuator, the voltage still drops to 3.8 V in, but the voltage to the reference input of the gauge is now 3.75 v retracted and 3.55 V at full 4" extension. The gauge is pegged out the entire time.
My attempt: many things, but I found that adding a 1k ohm resistor in parallel brought the voltage do the gauge in to working range (.1-1.03V) but the only .2 V difference between retracted and extended actuator means the gauge barely moves.
Additional info: I connected the gauge to a 1k ohm rotary potentiometer, the 5V from the gauge dropped to about 1.4 V approx at the input to the pot and I was able to control the gauge/reference voltage through it's entire range easily.
Can anyone help with what I should do here? Sorry for the long post but this is a technical problem (for me).
Thank you,
Justin
